N2WS-19463 - SSM backup fails with ValueError

N2WS-19463 - SSM backup fails with ValueError

Issue:

During backup of an EC2 instance with SSM option enabled,  agent might crash with following error in the cpm_agent.log:
ERROR:  backup_function(agent.py:2644)  Failing since backup function caught an exception for policy policy_name, schedule Immediate (ASAP), retry: 0.
Traceback (most recent call last):
  File "./agent.py", line 2638, in backup_function
  File "./agent.py", line 2847, in backup_function_internal
  File "./agent.py", line 399, in wait_for_snapshots
  File "./agent.py", line 820, in wait_for_ssm_agent_vss_backup_strategies
  File "./agent.py", line 888, in wait_for_snapshots_inner_volumes_handling
ValueError: list.remove(x): x not in list


Solution:
  1. Patch for v4.0.0b available and attached to this KB